Windscreen wiper device

ABSTRACT

A windscreen wiper device comprising an oscillating arm and a frame connected thereto for receiving a wiper blade ( 5 ), which frame includes a secondary yoke ( 3 ) which is pivotally connected to a primary yoke or carrier ( 1 ) about a pivot axis ( 2 ), wherein both the carrier primary yoke ( 1 ) and the secondary yoke ( 3 ) are of at least substantially U-shaped cross section at the location of their interconnection, and wherein said secondary yoke ( 3 ) is positioned at least substantially within said primary yoke ( 1 ) and wherein the primary yoke ( 1 ) includes a closed substantially cylindrical protuberance ( 8 ) in each leg of the U-shaped cross section at the location of the pivot axis ( 2 ), which protuberance ( 8 ) forms a substantially cylindrical bearing surface.

BACKGROUND OF THE INVENTION

The invention relates to a windscreen wiper device comprising anoscillating arm and a frame connected thereto for receiving a wiperblade, which frame includes a yoke which is pivotally connected to acarrier about a pivot axis, wherein both the carrier and the yoke are ofat least substantially U-shaped cross section at the location of theirinterconnection, and wherein said yoke is positioned at leastsubstantially within said carrier.

A windscreen wiper device of this kind is known from British patent No.2,139,528 (Trico-Folberth Ltd.). In this prior art windscreen wiperdevice, each leg of the U-shaped cross section of the yoke includes aprotrusion at the location of the pivot axis, which protrusion extendsinto a corresponding through hole in one of the legs of the U-shapedcross section of the carrier in the operating condition. In saidoperating condition, the yoke is pivots about a pivot axis relative tothe yoke. Before the operating condition is reached, the yoke is firstplaced into the carrier, whereby the legs of the U-shaped cross sectionof the carrier occupy an initial position, that is, extend outwardsrelative to the yoke. Then the legs of the U-shaped cross section of thecarrier are bent inwards by exerting an external force in inwarddirection relative to the yoke, wherein the protrusions of the yokeextend into the corresponding through holes in the carrier. The legs ofthe U-shaped cross section of the carrier remain in said bent position,thus securing the operating position.

One drawback of the windscreen wiper device as known from the aforesaidBritish patent publication is the fact that it has become apparent thatit is not possible to cut or saw the above-indicated through holes inthe legs of the U-shaped cross section of the carrier with sufficientprecision. In practice this means that some play will develop betweenthe protrusions of the yoke and the holes in the carrier after sometime. This play will even increase as a consequence of the legs of theU-shaped cross-section of the carrier springing back in outwarddirection (relative to the yoke) after some time. In that case there isabsolutely no question of a wear-resistant connection between the yokeand the carrier, nor of substantially frictionless pivoting of the yokeabout the pivot axis. Consequently, there is absolutely no question of adurable connection between the yoke and the carrier in accordance withthe aforesaid British patent. Another drawback of the prior artwindscreen wiper device is the fact that in particular dirt canaccumulate in the through holes that are present in the legs of theU-shaped cross section of the carrier, which likewise affects thedurability of the connection between the yoke and the carrier.

SUMMARY OF THE INVENTION

The object of the invention is to overcome the above drawbacks of theprior art and in particular to provide a windscreen wiper device whereinthe connection between the yoke and the carrier is durable and solid,i.e. wherein particularly there is no angular play between the carrierand the yoke.

In order to accomplish that objective, a windscreen wiper device of thekind mentioned in the introduction is according to the inventioncharacterized in that the carrier includes a closed substantiallycylindrical protuberance in each leg of the U-shaped cross section atthe location of the pivot axis, which protuberance forms a substantiallycylindrical bearing surface. In one preferred variant, the protuberancesextend outwards on either side relative to the yoke, the yoke beingprovided at the location of the pivot axis with a protrusion in each legof its U-shaped cross section, which protrusion pivotally engages in acorresponding protuberance of the carrier. Since the protuberancesextend outwards, the two protrusions of the yoke, which function asbearing supports, are spaced relatively far apart, as a result of whichthe forces on said bearings are relatively small. In another preferredvariant, the protuberances extend inwards on either side relative to theyoke, wherein the yoke includes a recess in each leg of its U-shapedcross section, at the location of the pivot axis, in which acorresponding protuberance of the carrier pivotally engages. In thisconnection, the term “closed protuberance” is understood to mean adished part, that is, a part of the material of the legs of the U-shapedcross section of the carrier that is locally pushed aside, in such amanner that no opening in the sense of a through hole is formed. In theformer preferred embodiment, the material is pushed outwards, whilst inthe latter preferred embodiment the material is pushed inwards. Animportant advantage of the closed protuberance or dished part is thatthe shape thereof can be determined with great precision by stamping orpunching, so that there is no question of play between the yoke and thecarrier. Another advantage is furthermore the fact that dirt fromoutside cannot accumulate in the protuberances.

In one preferred embodiment of a windscreen wiper device according tothe invention, the yoke is externally formed with a longitudinal groovein at least one leg of its U-shaped cross section, along which groove aprotuberance of the carrier is guided when the yoke is at leastsubstantially received in the carrier in the longitudinal direction ofthe carrier. This enables sliding movement of the yoke in the carrier inthe longitudinal direction of said carrier, wherein the formerlongitudinal groove functions as a guide for a protuberance of thecarrier, in which case said protuberance extends inwards relative to theyoke, of course.

The invention furthermore relates to a method of S manufacturing awindscreen wiper device according to the invention, wherein the twoclosed protuberances are stamped in the sheet material from which thecarrier is made before the material is given its U-shaped section. Inone preferred embodiment, the yoke is placed at least substantiallywithin the carrier and connected thereto in an initial position, inwhich protrusions formed in the legs of the U-shaped cross section ofthe yoke engage at least partially at the location of the pivot axis inprotuberances of the carrier extending outwards on either side relativeto the yoke, thus leaving some play between the yoke and the carrier,and wherein the yoke is then connected to the carrier in a finalposition, without play, by bending the legs of the U-shaped crosssection of the carrier inwardly relative to the yoke. In anotherpreferred embodiment, the yoke is placed at least substantially withinthe carrier and connected thereto in an initial position, whereinprotuberances of the carrier extending inwards on either side relativeto the yoke engage at least partially at the location of the pivot axisin recesses formed in the legs of the U-shaped cross section of theyoke, thus leaving some play between the yoke and the carrier, andwherein the yoke is then connected to the carrier in a final position,without play, by bending the legs of the U-shaped cross section of thecarrier inwardly relative to the yoke. In both embodiments theprotuberances according to the invention are dimensioned such that, evenwhen the legs of the U-shaped cross-section of the carrier will springback a little bit in outward direction relative to the yoke after beingbent in inward direction in the final position, angular play between thecarrier and the yoke does not occur.

It is noted that from French patent No. 2,453,757 (Ducellier et Cie.) aconnecting construction is known wherein a convex protrusion is presenton each leg of the U-shaped cross section of the yoke, which protrusionfits in a corresponding recess in each leg of the U-shaped cross sectionof the carrier. A cylindrical bearing surface is not provided here,however, so that there is absolutely no question of a properlyfunctioning and reliable connection between the yoke and the carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail hereafter with referenceto figures illustrated in a drawing, wherein:

FIGS. 1-6 refer to one embodiment; and

FIGS. 7-12 relate to the other embodiment.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 7 show a perspective view of a wiper frame, which consistsof a first yoke (1), which can be pivotally attached to an oscillatingarm of a windscreen wiper device of a vehicle at the location of pivotaxis (2). The first yoke (1) functions as the carrier of two secondaryyokes (3), which secondary yokes (3) function as the carriers of twotertiary yokes (4). All yokes are pivot-mounted in their respectivecarriers, so that a force exerted at the location of pivot axis (2) isdistributed more or less evenly over the ends of the tertiary yokes (4),capable of being transferred to a rubber wiper blade (5), which can befitted between the claws (6) of the tertiary yokes (4) and between theclaws (7) of the secondary yokes (3).

The pivoted joint between each yoke (3,4) and its respective carrier(1,3) is effected without the interposition of a special separate jointpart made of plastic material, for example, because only the first yoke(1) is made of metal and the other yokes (3,4) are made of plasticmaterial. In case all yokes (1,3,4) are made of metal, such a specialseparate plastic joint part is used after all.

FIGS. 2 and 8 show a perspective view on the manners the secondary yokes(3) are manoeuvred into the carrier (1), wherein in accordance with FIG.2 the secondary yokes (3) are slid inside the carrier (1) in thelongitudinal direction thereof, while according to FIG. 8 the secondaryyokes (3) are brought inside the carrier (1) in vertical direction, thatis perpendicular to the carrier (1). However, in both manners (FIGS. 2and 8) the secondary yokes (3) are clipped into the carrier in aninitial position. In the manner according to FIG. 2 closed substantiallycylindrical protuberances (8) in the legs of the U-shaped cross sectionof the pivot axis, extending inwards on either side relative to thesecondary yokes (3), are clipped into recesses (9) in the legs of theU-shaped cross section of the secondary yokes (3). However, in thisinitial position there is still play between the secondary yokes (3) andthe carrier (1), so that there is a “rattling” connection between them.In order to achieve a durable and reliable connection the secondaryyokes (3) are connected to the carrier (1) in a final position (withoutplay), by bending the legs of the U-shaped cross section of the carrier(1) inwardly relative to the secondary yokes (3). The above explainedinitial (before bending the legs) and final (after bending the legs)positions are shown in FIGS. 4, 5 on the one hand and FIG. 6 on theother hand, respectively. FIGS. 4, 5 and 6 are side views, whereas FIG.5 is a partial cross-sectional side view. The aforesaid closedsubstantially cylindrical protuberances (8) are manufactured through astamping or punching process, thereby accurately defining the shapethereof. The protuberances (8) are guided along grooves (10) on eitherside of the secondary yokes (3) in order to slide the latter inside thecarrier (1) in a controllable and easy manner. As can be seen from FIG.2, grooves (10) extend until the holes (9). Finally, the rubber wiperblade (5) is fixed to the frame (FIG. 3).

FIGS. 8-12 correspond to FIGS. 2-6 on the understanding that FIGS. 8-12relate to the second embodiment, wherein the protuberances (8′) extendoutwards on either side relative to the secondary yokes (3). Therefore,the yokes (3) are provided at the location of the pivot axis withprotrusions (9′) in the legs of the U-shaped cross section thereof. Inthe initial position mentioned before (FIGS. 10 and 11) they are clippedinto the protuberances (8′), thus realizing a “rattling” connectionbetween the secondary yokes (3) and the carrier (1), whereas in thefinal position (FIG. 12) the legs of the U-shaped cross section of thecarrier (1) are bent inwardly relative to the secondary yokes (3), thusachieving an excellent connection. Also the protuberances (8′) are madeby a stamping or punching process.

What is claimed is:
 1. A windscreen wiper device comprising anoscillating arm and a frame connected thereto for receiving a wiperblade, which frame includes a yoke which is pivotally connected to acarrier about a pivot axis, wherein both the carrier and the yoke are ofat least substantially U-shaped cross section at the location of theirinterconnection, and wherein said yoke is positioned at leastsubstantially within said carrier, characterized in that said carrierincludes a closed substantially cylindrical protuberance in each leg ofthe U-shaped cross section at the location of the pivot axis, whichprotuberance forms a substantially cylindrical bearing surface, andwherein said yoke is externally formed with a longitudinal groove in atleast one leg of its U-shaped cross section, along which groove saidprotuberances of said carrier are guided when said yoke is at leastsubstantially received in said carrier in the longitudinal direction ofsaid carrier.
 2. A windscreen wiper device according to claim 1, whereinsaid protuberances extend inwards on either side relative to the yoke.3. A windscreen wiper device according to claim 2, wherein the yokeincludes a recess in each leg of its U-shaped cross section, at thelocation of the pivot axis, in which a corresponding protuberance of thecarrier pivotally engages.
 4. A windscreen wiper device according toclaim 1, wherein said carrier is made of a metal and wherein said yokeis made of a plastic material.
 5. A method of manufacturing a windscreenwiper device according to claim 1, wherein the two closed substantiallycylindrical protuberances are stamped in the sheet material from whichthe carrier is made before the material is given its U-shaped crosssection.
 6. A method according to claim 5, wherein said longitudinalgroove is formed externally in at least one leg of the U-shaped crosssection of the yoke, along which groove said protuberance of saidcarrier is guided when the yoke is at least substantially received insaid carrier in the longitudinal direction of said carrier.